为了探究导体电阻与长度的关系,小强把一根较长的镍铬合金线AB组装成如图所示的电路,E、F是电夹.
- How long does it take to get to the airport?
- Forty minutes. But it's foggy today. I'm not sure _________ the highway will be closed soon. Let's set off earlier.
已知椭圆 x2a2 + y2b2 =1(a>b>0)的离心率为 22 ,且过点(2, 2 ).
下列事实能说明铝的金属活动性比铁或铜强的是( )